Characterization of thunderclap headache in a reversible cerebral vasoconstriction syndrome case series

Objectives: To empirically address how thunderclap headache (TCH) is described in a relevant real-world setting. Background: TCH refers to a highly recognizable description of a severe headache that reaches maximum severity within 1 minute and endures for at least 5 minutes. The use of a numerical rating scale (NRS) to appraise TCH severity, as well as assessment of TCH progression in patients with pre-existing headache at the time of TCH onset has not been previously evaluated. Methods: This was a retrospective case series of adults with a diagnosis of reversible cerebral vasoconstriction syndrome (RCVS), identified through a search of the electronic health record. Individuals meeting International Classification of Headache Disorders, 3rd Edition criteria for acute headache attributed to RCVS were included. Attacks described using a verbal descriptor scale (VDS), NRS, or both were recorded to evaluate acute headache characteristics. Results: In all, 56 individuals with available descriptions of 120 acute headaches were included in the study analysis. Patients were female (35, 62.5%) with a median age of 46 (range: 19–67). The majority of patients reported a RCVS trigger (39, 69.6%). Acute headaches were characterized using a VDS (52, 43.3%), NRS (51, 42.5%), or both (17, 14.1%). Acute headaches were always described as severe when a VDS was utilized, and with a median NRS of 10 (range: 4–10). Four patients (7%) did not have a single headache characterized as either severe or with a NRS 8 or greater. In the 10 cases for which there was a pre-TCH baseline headache, it was either rated as mild or with a median NRS of 3 (range: 2–6). Conclusions: TCH in RCVS can be recognized using either VDS or NRS, with a broader range of peak intensities than previously recognized. TCH remains recognizable despite pre-existing baseline headache.